#!/bin/perl -w
use strict;

my %hash;

while( <>)
  { # note: the left part should be just one character
    $hash{$2}= $1 if( m/^\s*(.)\s*::=\s*([^\s]*)\s*$/);
  }

while( my($key, $value)= each %hash)
  { print "/$key/ ::= /$value/\n"; }

##</code><code>##

#!/bin/perl -w
use strict;

my %hash;

while( <>)
  { my($key, $value)= m/^\s*(.)\s*::=\s*([^\s]*)\s*$/;
     $hash{$key} ||= [];          # create an array ref if needed
     push @{$hash{$key}}, $value; # add to the array
  }

while( my($key, $values)= each %hash)
  { # the values are in @{$values}
    print "/$key/ ::= /", join( '/', @{$values}), "/\n"; }